Belar FMM-4A FM Frequency Monitor

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Belar FMM-4A

Summary

The Belar FMM-4A is a highly accurate digital FM frequency monitor designed especially for automatic broadcast transmitter monitoring. The counter will accurately monitor FM Carrier, Pilot, and SCA Frequencies. A large 3½ digit LED display provides a range of ±19.99 kHz for Carrier, ±1999 Hz for SCA, and ±10 Hz for Pilot. Front panel LED indicators are provided to warn of low level input or loss of any monitoring frequencies. To prevent false alarms, the FMM-4A inhibits the off-frequency alarms until three successive errors are detected. Two levels of alarm are provided for Carrier deviations. An alarm is also provided to indicate an invalid count, which could result from too low an input level or a malfunction with the counter. An optional alarm relay board is available.

Features

Features

Carrier

  • RF or LO and IF Inputs (when RFA-4 or RFA-1A is used)
  • ±1 kHz Off-Frequency Alarm
  • ±2 kHz Off-Frequency Alarm
  • Low-Level Alarm
  • FM Averaging Frequency Switch

Pilot *

  • ±2 Hz Off-Frequency Alarm
  • Low-Level Alarm

SCA *

  • ±500 Hz Off-Frequency Alarm
  • Low-Level Alarm

Invalid Count Alarm
Large 3½ digit LED display
Low profile design
Designed for ATS Operation

Option 01:  Eight Alarm Relay Card

Technical Specification

Technical Specification

Frequency Range:   
see below

Display: 
Large 3½ digit LED

Gate Time:    
2 seconds

Time Base:
6 MHz

Time Base Output:  
6 MHz TTL compatible level

Invalid Count Alarm:   
prevents false counts due to low level or problem in counter

Level Alarms:      
3 LED Indicators

Carrier
Frequency Range
80 MHz to 120 MHz

Accuracy
50 Hz (25 – 50 degrees C)

Sensitivity
RF(LO/IF) – (200/100)mV

Resolution
±10 Hz

Range
±19.99 kHz

Off-Frequency Alarms
±1 kHz & ±2 kHz

Pilot*

Frequency Range
19 kHz ± 10 Hz

Accuracy
0.01 Hz

Sensitivity
500 mV

Resolution
±0.1 Hz

Range
±10 Hz

Off-Frequency Alarms
±2 Hz

SCA *

Frequency Range
67 kHz direct or follows range of Belar SCM-2 SCA monitor

Accuracy
0.1 Hz

Sensitivity
500 mV

Resolution
±1 Hz

Range
±1999 Hz

Frequency Alarms
±500 Hz

Dimensions

1.75″H x 12″D x 19″W (EIA Rack Mount)

Power Requirements
115/230 VAC, 50/60 Hz

* If the BELAR FMS-2 or FMSA-1 is not used for obtaining a pure pilot and/or the BELAR SCM-2 is not used for obtaining a pure subcarrier, a filtered source for pilot and/or 67 KHz subcarrier is required.

© Copyright 1999 Belar Electronics Laboratory, Inc. All rights reserved.

New in 2015 – 3 Year Factory Warrant to all Belar Products 

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